Processing device and processing method suitable for processing multiple lens blanks into finely ground products

ABSTRACT

A processing device suitable for processing multiple lens blanks into a finely ground product, the processing device including two processing fixtures, each including a fixture body with a curved surface. There are three grooves having centers disposed on the same circumferential surface. One of the processing fixtures corresponds to the inner surface of the groove as a flat surface, and the other processing fixture corresponds to the concave surface of the groove as a curved surface. The invention also discloses a method for processing a plurality of lens blanks into a finely ground product by using the processing device. The invention can directly perform the fine grinding processing of multiple cylindrical lens blanks, thereby eliminating a milling process and reducing the production cost while meeting the required thickness, radius of curvature and appearance of the finished product.

PRIORITY CLAIM AND RELATED APPLICATIONS

This non-provisional application claims the benefit of priority from Chinese Pat. App. No. 2021111064276 filed on Sep. 22, 2021. Said application is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION 1. The Field of the Invention

The invention relates to a processing device suitable for processing a plurality of lens blanks into finished products using a processing device.

2. Background Art

At present, the processing method of cold-worked lens products is to use milling, fine grinding, polishing and edging processes to obtain finished lens products. Although the above-mentioned processing methods have many steps, high costs and low efficiency, the reason the above-mentioned processing methods are used is that existing precision grinding molds cannot fine grind lens blanks directly and can only be used to fine grind curved lens. Therefore, lens blanks need to be milled before fine grinding. Moreover, with existing precision grinding molds, the precision grinding of multiple lenses cannot be realized.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a processing device that can directly process lens blanks into finished products without milling. Another object of the present invention is to provide the use of the processing device to process multiple lens blanks into finished products using the present device and method.

The processing device is suitable for processing multiple lens blanks into finely ground products according to the present invention, includes two processing fixtures, each of the processing fixtures including a fixture body with a curved surface. There are three grooves having centers that are disposed on the same circumferential surface. One of the processing fixtures corresponds to the inner surface of the groove as a flat surface, the concave surface of the groove is used to place the lens blank, and the other processing fixture corresponds to the concave surface of the groove. The concave surface is a concave groove used to place the semi-finished product having one surface that has been finely ground.

A plastic annular ring is arranged in the groove, and the annular ring is fixed on the inner side wall of the groove by glue. The annular ring has a blocking effect on the edge of the lens, thereby limiting the movement of the lens in the front and rear, left and right directions. The annular ring has good wear resistance and can confine the lens in the groove, that is, the function of the annular ring is to fix the lens placed in the groove of the fixture body.

The depths of the three grooves are the same, and the depth of the grooves is based on the arc-shaped curved surface of the machining fixture.

The processing device also includes at least one fine grinding mold and each fine grinding mold includes an arc-shaped groove with an opening at the top and a handle for fixed connection with an external rotating shaft.

The curvature of the arc-shaped working surface of the fine grinding mold is consistent with the curvature of the corresponding surface of the fine grinding product.

The method for processing a plurality of lens blanks into a finely ground product by using the above-mentioned processing device includes the following steps:

(a) Based on the requirements of the finished lens for the lens center thickness and radius of curvature, inversely deduce the requirements for the lens center thickness and curvature radius of the finely ground product, design the corresponding processing fixture dimensional parameters, including the curvature of the arc surface of the machining fixture, the size of the groove and the arrangement of the groove;

(b) Curvature of the arc surface of the processing fixture: During processing, the resistance cloth is placed in the groove. The curvature radius of the arc surface of the fixture body R3+the thickness of the resistance cloth=the curvature radius of the corresponding surface of the lens finishing product R1/R2 (curvature of the lens to be processed. The curvature value of the surface is determined and the curvature of the fixture body is based on a circle center, that is, the arc surface of the fixture body and the surface to be processed are concentric circles after processing).

Regarding the size of the groove, the inner diameter of the groove is the sum of the diameter of the lens and the thickness of the annular ring.

Regarding the arrangement of the grooves, the three grooves are evenly distributed on the arc surface of the fixture body and the angles between the center lines of the three grooves and the center line of the fixture body are equal. The adjacent parts of the upper three uniform grooves must have a certain minimum distance apart so that the edges of the three lenses placed in the groove of the fixture body will not touch. The adjacent edges of the three annular rings will not touch. At the same time, the wall thickness formed by the distance between the adjacent parts of the three grooves on the fixture body also needs to ensure the strength of the wall. Generally, the adjacent distance between the grooves of the fixture body is greater than the minimum distance, The distance is provided to ensure the strength of the wall thickness to prevent deformation during use that can affect the position accuracy of the groove;

(c) The lens blank is processed on the first side and the three lens blanks are respectively placed in the three grooves of the processing fixture 1. The processing fixture 1 with the lens blank is pressed on the fine grinding mold by the pressure head of the center-of-ball machine. The curvature of the arc working surface of the mold is adjusted based on the curvature requirements of the corresponding surface of the fine grinding product. The processing fixture 1 is passively rotated by the high-speed rotating fine grinding mold;

(d) After processing one surface of the lens blank, a semi-finished product is obtained. When the other surface of the lens blank is processed, the three semi-finished products are placed in the three grooves of the processing fixture 8. The processing fixture 8 equipped with the semi-finished product is swung down. The press head is pressed on the fine grinding mold. The curvature of the arc working surface of the fine grinding mold is adjusted based on the curvature requirements of the corresponding surface of the fine grinding product. The machining fixture 8 is passively rotated under the drive of the high-speed rotating fine grinding mold to yield the finished product.

In step (c) and step (d), the pressure on the processing fixture is 0.5-10 kg and the rotation speed of the fine grinding mold is 800-3500 rpm.

In steps (c) and (d), the ratio of the diameter of the fine grinding mold to the diameter of the machining fixture is 1.5:1.

In step (c) and step (d), the curvature of the arc working surface in the fine grinding mold is determined based on the curvature of the corresponding surface of the fine grinding product. After the fine grinding mold with the corresponding curvature is used for processing for 3 to 5 seconds, the processing is stopped, the lens is taken out, and the curvature of the machined surface is measured. If it meets the requirements, go to the next step. If it does not meet the requirements, use the curvature of the arc working surface of the finishing mold to trim the curvature of the arc working surface of the finishing mold. The curvature of the arc working surface of the finishing mold corresponds to the finished product. The curvature of the curved working surface of the finishing mold is the same as the curvature of the corresponding surface of the fine grinding product. The diameter of the curved working surface of the fine grinding mold is larger than that of the curved working surface of the processing fixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the structure of the processing fixture 1;

FIG. 2 is a top view of the processing fixture;

FIG. 3 is a schematic diagram of the structure of a semi-finished product obtained by using a processing fixture 1;

FIG. 4 is a schematic diagram of the structure of the processing fixture 8;

FIG. 5 is a schematic diagram of the structure of the finished product obtained by using the processing fixture 8;

FIG. 6 is a schematic diagram of the structure of the processing fixture 1 equipped with the lens blank placed in the fine grinding mold;

FIG. 7 is a schematic diagram of the structure after one side is processed;

FIG. 8 is a schematic diagram of the structure of the processing fixture 8 equipped with the semi-finished products of precision grinding placed in the precision grinding mold;

FIG. 9 is a schematic diagram of the structure after both sides are processed.

PARTS LIST

-   1—processing fixture -   2—annular ring -   3—resistance cloth -   4—groove -   5—shaft handle -   6—surface -   7—surface -   8—processing fixture -   9—fine or precision grinding mold or die -   10—groove -   11—fixture body -   80—fine or grinding product -   90—semi-finished product -   100—lens blank

PARTICULAR ADVANTAGES OF THE INVENTION

Compared to the prior art, the present invention has significant advantages. The present invention can directly perform the fine grinding of multiple cylindrical lens blanks, so as to meet the required thickness, radius of curvature and appearance of the finely ground finished product. A milling process is eliminated and the production cost is reduced because multiple lens blanks can be processed at one time, the number of processing output is doubled, which greatly improves the production efficiency. The radius and thickness change during the lens fine grinding process are lower than the frequency of single-piece processing changes. The repair is relatively simple, thus ensuring the quality of the finished product.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

As shown in FIGS. 1 to 5 , the present invention is applicable to a processing device for processing multiple lens blanks into finely ground products. It includes two processing fixtures, i.e., processing fixture 1 and processing fixture 8. Each processing fixture includes a curved surface. The fixture body 11 is provided with three grooves 10 on the arc surface with the centers on the same circumferential surface. The inner surface 7 of the corresponding groove of the machining fixture 11 is a flat surface. The lens blank 100 is placed therein, the concave inner surface 6 of the groove corresponding to the machining fixture 8 is a curved surface and the concave groove 10 having inner concave surface 6 is a curved surface that is used to place the semi-finished product 90 having one surface has been finely ground.

The processing fixture is made of metal or plastic. It has a spherical arc surface with multiple grooves on the top. The centers of the grooves are evenly distributed on the arc surface. The curvature surface of the groove and the curvature surface of the spherical groove are uniformly distributed. It is consistent to ensure the uniformity of the distribution of the three grooves. A plastic annular ring 2 is provided in the groove 10, and the annular ring 2 is fixed on the inner side wall of the groove 10 by glue. The annular ring 2 has a blocking effect on the edge of the lens in the groove, restricting the movement of the lens in the front and rear, left and right directions in the groove 10 of the fixture body 11. The depths of the three grooves 10 are the same, and the depth of the groove 10 is based on the arc-shaped curved surface of the machining fixture. The present invention is suitable for processing a plurality of lens blanks into a fine grinding product. The processing device also includes at least one fine grinding mold 9, each of the fine grinding mold 9 includes an arc-shaped groove 4 with an opening at the top and a fixed connection with an external rotating shaft handle 5. The curvature of the arc-shaped working surface 4 of the fine grinding mold 9 is consistent with the curvature of the corresponding surface of the fine grinding product. The arc-shaped working surface 4 of the fine grinding mold 9 is made of metal material and a diamond layer is laid on the arc-shaped working surface 4.

During processing, the adjustment of the lens thickness is controlled based on the fine grinding time and the curvature radius of the lens corresponding surface is controlled based on the radius of curvature of the fine grinding mold. Fix the handle 5 of the fine grinding mold 9 to the main shaft of the machine through a fixture, place the lens blank on the machining fixture and then place the processing fixture on the arc working surface 4 of the fine grinding mold 9, adjust the machine parameters and start the machine. When the machine is started, a liquid will be injected into the arc-shaped working surface 4 of the fine grinding mold 9 automatically. Through the relative movement of the high-speed rotating fine grinding mold 9 and the processing surface of the passively rotating lens blank 4, the cutting action is generated and the processing requirements for the curved surface of the lens blank are met.

The method for processing a plurality of lens blanks into a finely ground finished product by using the above-mentioned processing device specifically includes the following steps:

(a) Based on the requirements for the lens center thickness and curvature radius of the finished lens product, the requirements of the precision grinding product for the lens center thickness and curvature radius are deduced. Based on the precision grinding product requirements for the center thickness and curvature radius of the lens corresponding to the lens, the size parameters of the corresponding processing fixture are designed, including the curvature of the arc surface of the machining fixture, the size of the groove and the arrangement of the groove;

(b) Curvature of the arc surface of the processing fixture: During processing, the resistance cloth 3 is placed in the groove 10 and the outer diameter of the resistance cloth 3 is slightly smaller than the inner diameter of the groove 10 and is placed in the groove 10. The curvature radius of the arc surface of the fixture body 11 is R3+the thickness of the resistance cloth 3=the radius of curvature R1/R2 of the corresponding surface of the lens finishing product (the radius of curvature corresponding to the surface to be processed of the lens is determined and the curvature of the fixture body is based on a circle center, that is, the arc of the fixture body and the arc to be processed are concentric circles). The size of the groove: the inner diameter of the groove is the sum of the diameter of the lens and the thicknesses of the annular ring. the arrangement of the grooves. The arrangement of the groove: The three grooves are evenly distributed on the arc surface of the fixture body, the included angles between the center lines of the three grooves and the center line of the fixture body are equal. The adjacent parts of the three uniformly distributed grooves on the fixture body must have a certain minimum distance between them to facilitate placement. The edges of the three lenses in the groove of the fixture body will not touch. At this time, the adjacent edges of the three annular rings placed in the groove of the fixture body will not touch. At the same time, the wall thickness formed by the distance between the adjacent parts of the three grooves on the fixture body also needs to ensure the strength of the wall. Generally, the adjacent distance between the grooves of the fixture body is greater than the minimum distance, The distance is provided to ensure the strength of the wall thickness to prevent deformation during use that can affect the position accuracy of the groove;

(c) As shown in FIGS. 6-7 , the first side of the lens blank is processed and the three lens blanks 100 are placed in the three grooves 10 of the processing fixture 1. The processing fixture 1 with the lens blank 100 is pressed by the pressure head of the center-of-ball machine on the fine grinding mold 9. The ratio of the diameter of the fine grinding mold 9 to the diameter of the machining fixture is 1.5:1, the speed is 1800 rpm, and the pressure loaded on the machining fixture is 1 kg. The curvature of the arc working surface 4 in the fine grinding mold is based on the curvature R1 of the corresponding surface of the finished product. The fine grinding mold that corresponds to the curvature is used to process for 3-5 s. Then processing is stopped, the lens is taken out, the curvature R1 of the processed surface is measured. If it meets the requirements, go to the next step. If it does not meet the requirements, use the curvature of the arc working surface of the fine grinding mold to trim the curvature of the arc working surface of the fine grinding mold. The curvature of the arc working surface of the fine grinding mold is the same as the curvature R1 of the corresponding surface of the fine grinding product;

(d) As shown in FIGS. 8-9 , after processing one surface of the lens blank, a semi-finished product 90 is obtained and the other surface of the lens blank is processed. Place three semi-finished products 90 in the three grooves of the machining fixture 8. In 10, the machining fixture 8 equipped with the semi-finished product 90 is pressed by the pressure head of the center-of-ball machine on the fine grinding mold 9. The curvature of the arc working surface 4 of the fine grinding mold 9 is adjusted based on the curvature R2 of the corresponding surface of the finished product. The machining fixture 8 is driven by the high-speed rotating fine grinding mold 9 to passively rotate to yield a fine grinding product 80. The radii of curvature of the upper and lower curved surfaces of the finished product 80 are the same. The ratio of the diameter of the fine grinding mold 9 to the diameter of the machining fixture is 1.5:1, the speed is 1800 rpm and the pressure applied to the machining fixture is 1 kg. The curvature of the arc-shaped working surface 4 in the fine grinding mold is determined based on the curvature R2 of the corresponding surface of the fine grinding product. After 3-5 seconds of processing with the fine grinding mold corresponding to the curvature, the processing is stopped, the lens is taken out and the curvature of the processed surface is R2 is measured. If it does not meet the requirements, use the curvature of the arc working surface of the fine grinding mold to trim the curvature of the arc working surface of the fine grinding product. The curvature of the arc working surface of the fine grinding mold corresponds to the finished product. The curvature of the curved working surface of the fine grinding mold is the same as the curvature R2 of the corresponding surface of the fine grinding product. The diameter of the curved working surface of the fine grinding mold is larger than that of the curved working surface of the processing fixture. 

What is claimed herein is:
 1. A processing device for processing a plurality of lens blanks into finely ground products, said processing device comprising two processing fixtures, each of said two processing fixtures comprises a fixture body comprising a curved surface, three grooves each comprising a center, said three grooves are configured such that said centers are disposed on said curved surface of each said processing fixture, wherein a first of said two processing fixtures comprises a surface of each of said three grooves that is a flat surface and a second of said two processing fixtures comprises a surface of each of said three grooves that is a curved surface.
 2. The processing device according to claim 1, wherein each said groove of said first and second of said two processing fixtures comprises a plastic annular ring fixed on an inner side wall of each said groove by a glue.
 3. The processing device according to claim 1, wherein the depths of said three grooves of are the same for each said processing fixtures and the depths of said three grooves are based on an arc-shaped curved surface of each said processing fixtures.
 4. The processing device according to claim 1, further comprising a fine grinding mold comprising an arc-shaped groove with an opening at one end and a handle configured to be fixedly connected to an external rotating shaft.
 5. The processing device according to claim 4, wherein the curvature of an arc working surface of said fine grinding mold is consistent with the curvature of a corresponding surface of finished products of the finely ground products.
 6. A method for processing a plurality of lens blanks into finely ground products by using the processing device of claim 1, said method comprising: (a) inversely deducing requirements for the lens center thickness and curvature radius of the finely ground products based on the requirements for finished lens products for the lens center thickness and curvature radius, designing said two processing fixtures based on the requirements of the finished lens products for the center thickness and curvature radius of the finished lens products, wherein the lens center thickness and curvature radius comprise surface dimensional parameters comprising the curvature of the arc surface of said two processing fixtures, the size of the three grooves of each said processing fixtures and the arrangement of the three grooves of each said processing fixtures; (b) disposing a resistance cloth in each said groove of said first of said two processing fixtures, wherein the curvature radius of the arc surface of the fixture body of said first of said two processing fixtures plus the thickness of the resistance cloth is equal to the curvature radius of a corresponding surface of a lens fine grinding product, the inner diameter of the groove is the sum of the diameter of the lens and the thicknesses of an annular ring, the three grooves of each said processing fixture are evenly distributed on the arc surface of each said processing fixture and the included angles between the center lines of the three grooves of each said processing fixture and the center line of the fixture body of each said processing fixture are equal; (c) performing a first surface processing act on the lens blank and placing the three lens blanks in the three grooves of said first of said two processing fixtures, pressing said first of said two processing fixtures on the fine grinding mold by the pressure head of the center-of-ball machine, adjusting the curvature of the arc-shaped working surface of the fine grinding mold based on the curvature requirements of the corresponding surface of the fine grinding products and passively rotating said first of said two processing fixtures at high speed under the fine grinding mold to process one surface of the lens blanks to yield semi-finished products; and (d) placing the semi-finished products in said three grooves of said second of said two processing fixtures, pressing said second of said two processing fixtures on the fine grinding mold by the pressure head of the center-of-ball machine, adjusting the curvature of the arc working surface of the fine grinding mold based on the curvature requirements of the corresponding surface of the fine grinding product and passively rotating said second of said two processing fixtures at high speed under the find grinding mold to process the semi-finished products to yield finished products.
 7. The method according to claim 6, wherein in step (c) and step (d), the pressure on the processing fixture is 0.5-10 kg and the speed of the fine grinding mold is 800˜3500 rpm.
 8. The method according to claim 6, wherein in step (c) and step (d), the ratio of the diameter of the fine grinding mold to the diameter of one of said processing fixtures is 1.5:1.
 9. The method according to claim 6, wherein in step (c) and step (d), the curvature of the arc working surface in the fine grinding mold is based on the curvature of the corresponding surface of the finished products and upon processing 3˜5 s with the fine grinding mold corresponding to the curvature of the arc working surface, said processing is stopped, the plurality of semi-finished products are taken out to be measured for the curvature of the processed surfaces, wherein said plurality of semi-finished products are processed until the curvatures of the plurality of semi-finished products meet the curvatures of the finished products.
 10. The method according to claim 6, wherein in step (c) and step (d), the curvature of the arc working surface in the fine grinding mold is based on the curvature of the corresponding surface of the finished products and upon processing 3˜5 s with the fine grinding mold corresponding to the curvature of the arc working surface, said processing is stopped, the plurality of lens blanks are taken out to be measured for the curvature of the processed surfaces, wherein said plurality of lens blanks are processed until the curvatures of the plurality of lens blanks meet the curvatures of the finished products. 